Treating polyester filament with a surface active compound to permit lagging before drawing



United States Patent O 3,329,758 TREATING POLYESTER FILAMENT WITH A SUR- FACE ACTIVE COMPOUND TO PERMIT LAG- GING BEFORE DRAWING Herbert S. Morgan, Jr., Apex, and Horace M. Robinson, Jr., Cary, N.C., assignors to Monsanto Company, a corporation of Delaware N Drawing. Filed June 17, 1963, Ser. No. 288,522

4 Claims. (Cl. 264290) This invention relates to an improved method for producing articles prepared from high molecular weight synthetic linearpolyesters. More particularly, it relates to an improved method for improving the surface characteristics of articles prepared from synthetic linear polyesters.

It is well known to apply finishing agents to textile materials in order to impart to the textile materials certain desirable properties, such as antistatic protection, stiffness, sizing, softness, lubricity, water repellency, shrinkage resistance, flame retardance, and the like. In addition, in the manufacture of filament yarns from such synthetic linear polymers as the polyamides, polyesters, polyalkylenes, polyurethanes, polycarbonates, acrylonitrile polymers, and the like, it has been known that ultimate yarn tenacity can be greatly increased by employing the technique of drawing, which comprises stretching the yarn filaments after their formation to increase molecular orientation.

Although the drawing operation can be conducted by various means, a common procedure is to employ two filament advancing devices generally known as a feed roll and draw roll. Filament stretching is achieved by running these rolls at differential speeds with the amount of stretching or drawing being determined by the ratio of the peripheral speeds of the two rolls. In order to localize the point at which stretching occurs, a braking device is sometimes placed between the feed roll and draw roll. Generally, the braking device consists of a pin, called the draw pin, around which the yarn is wrapped a number of times. The draw pin introduces frictional drag 0n the moving filaments which causes stretching to take place in the area of the draw pin. The introduction of frictional drag to localize stretching is utilized in those instances where there is a tendency for non-uniform drawing to occur since greater uniformity can be obtained by employing this procedure.

It has been known that the drawing operation can sometimes be facilitated when the yarn temperature is elevated during drawing. The heating may be carried out by inserting a hot pin, a hot plate, or hot fluid bath between the feed roll and draw rolls of the drawing apparatus or by using a heated feed roll. Elevated temperatures are effective because intermolecular forces are diminished by the resulting increase in molecular activity, and therefore the ratio of the force required to draw the yarn to that required to break it is lessened. Permissible temperatures which may be used in hot drawing vary somewhat with the nature of the polymer from which the yarn is formed, since the maxium temperature which can be employed is limited by the polymer sticking point. It is a common practice to employ a hot drawing technique when processing yarn for use in products which require great tensile strength, as for example in the manufacture of reinforcement cords for inflatable tires.

A particularly troublesome problem encountered when drawing at either ambient or elevated temperatures is the occurrence of filament breakage during the drawing oper- 3,329,758 Patented July 4, 1967 ation. Thus, at times one or more individual filaments in the thread line may break and wrap around the draw roll or as sometimes happens the entire thread line may break, in which case production is stopped until adjustment can be made. Such filament breakage not only affects labor requirements and productivity, but the product quality is also affected in an adverse manner.

The pricipal cause of filament break-age while drawing is the buildup of excessive tension of the yarn which in turn is intensified, for the most part, by inter-filament friction and by the generation of excessive friction as the yarn passes over the draw pin when such device is employed.

It is known that excessive yarn tensions resulting from the development of unduly high and variable frictions during drawing can be reduced by applying to the yarn various anti-friction conditioning agents before it is drawn. These agents are generally applied from an aqueous vehicle rather than from non-aqueous systems to afford a more uniform distribution and better control over the amount of active agent which is deposited on the yarn. These factors are of considerable importance and cannot be controlled when a non-aqueous solvent, for example, is employed as a vehicle. Non-aqueous solvents are highly objectionable because of problems of toxicity and of high solvent retention on the yarn, and also a resulting serious impairment of the drawing operation.

In the case of fibers prepared from high molecular weight synthetic linear polyesters, it is known that these fibers when freshly spun may be slowly cold drawn by hand or rapidly hot drawn over heated surfaces by the methods discussed above. However, when undrawn polyester fibers are allowed to age or lag, the polyester fiber is known to change its amorphous nature and the aged fiber crystallizes causing it to become very brittle and difiicult to draw uniformly. This condition is magnified during the drawing step where the individual filaments break at the draw pin and by filament wraps accumulating on the drawing roll-s as discussed previously. In some cases, slow drawing speeds can be used to help alleviate this condition to some extent, but this seriously limits the quantity of yarn or fiber which can be drawn in a given period of time. Although the tendency for brittleness, excessive yarn tensions, and the like, to develop during lagged drawing of polyester fibers may be reduced somewhat by pretreatment With certain known conditioning agents of the prior art, there is a continuing need for treating compositions which are capable of greater effectiveness in coping with the problem.

It is an object of this invention to improve the process step of drawing high molecular weight synthetic linear polyesters.

It .is another object of the present invention to provide static protection and lubrication for impoved processing of high molecular weight synthetic linear polyester filaments.

It is a further object of this invention to provide a method of reducing the fuming tendency of high molecular weight synthetic linear polyester filament finishes during a hot drawing step.

Other objects and advantages of this invention will I them with an aqueous emulsion, the solids content of which comprises a cationic surface active quaternary ammonium compound, prior to the drawing step. It has further been found that this procedure not only facilitates the drawing operation, but that, in addition thereto, substantial advantages are imparted to the ultimate yarn product. For example, a finish formulation, as described above, has been found to maintain improved drawing properties and stability to heat in a high molecular weight synthetic linear polyester yarn after a lag time of about 30 days.

The cationic surface active agents used in this invention are the quaternary ammonium compounds having the formula wherein R represents an alkyl radical having more than 10 carbon atoms and R represents an alkyl radical having less than carbon atoms. Examples of such quaternary ammonium compounds represented by the above formula include soya dimethyl ethyl ammonium ethosulfate, in which the alkyl groups represented by R are derived from the fats contained in the soya oil, consisting chiefly of saturated 16 and 18 carbon aliphatic carboxylic acids as their esters, lauryl dimethyl ethyl ammonium methosulfate, myristyl dimethyl ethyl ammonium ethosulfate, palmityl dimethyl ethyl ammonium propiosulfate, margaryl dimethyl ethyl ammonium butyrosulfate, stearyl dimethyl ethyl ammonium ethosulfate, oleyl dimetyl ethyl ammonium methosulfate and linoleyl dimetyl ethyl ammonium ethosulfate.

The synthetic linear condensation polyesters contemplated in the practice of this invention are those formed from dicarboxylic acids and glycols, and copolyesters or modifications of these polyesters and copolyesters. In a highly polymerized condition, these polyesters and copolyesters can be formed into filaments and the like.

The polyesters and copolyesters specifically useful in the instant invention are those resulting from heating one or more of the glycols of the series HO(CH OH, is which n is an integer from 2 to 10, with one or more dicarboxylic acids or ester-forming derivatives thereof. Among the dicarboxylic acids and ester-forming derivatives thereof useful in the present invention are terephthalic acid, isophthalic acid, sebacic acid, adipic acid, p-carboxyphenoacetic acid, succinic acid, p,p-dicarboxybiphenol, p,p-dicarboxycarbanilide, p,p'-dicarboxythiocarbanalide, p,p-dicarboxydiphenylsulfone, p-carboxyphenoxyacetic acid, p-carboxyphenoxypropionic acid, p-carboxyphenoxybutyric acid, p-carboxyphenoxyvaleric acid, p-carboxyphenoxyhexanoic acid, p-carboxyphenoxyheptanoic acid, p,p'-dicarboxydiphenylmethane, p,p'-dicarboxydiphenylethane, p,p-dicarboxydiphenylpropane, p,p-dicarboxydiphenylbutane, p,p'-dicarboxydiphenylpentane, p,p'-dicarboxydiphenylhexane, p,p'-dicarboxydiphenylheptane, p,p'- dicarboxydiphenyloctane, p,p'-dicarboxydiphenoxyethane, p,p-dicarboxydiphenoxypropane, p,p-dicarboxydiphenoxybutane, p,p-dicarboxydiphenoxypentane, p,p'-dicarboxydiphenoxyhexane, 3-alkyl 4-(beta-carboxy ethoxy) benzoic acid, oxalic acid, glutaric acid, pimelic acid, suberic acid, azelaic acid and the dioxy acids of ethylene dioxide having the general formula,

wherein n is an integer from 1 to 4, and the aliphatic and cycloaliphatic aryl esters and half esters, ammonium and amine salts, and the acid halides of the above-named compounds and the like. Examples of the glycols which may be employed in practicing the instant invention are ethylene glycol, trimethylene glycol, tetramethylene glycol, decamethylene glycol, and the like. Polyethylene terephthalate, however, is preferred because of the ready availability of terephthalic acid and ethylene glycol, from which it is made. It also has a relatively high melting point of about 250 through 255 C. and this property is particularly desirable in the manufacture of filaments in the textile industry.

Among the modified polyesters and copolyesters which are useful in the practice of the present invention are those polyesters mentioned above modified with dialkylesters of saturated essentially linear aliphatic dicarboxylic acids containing 20 carbon atoms having the general formula wherein R and R are alkyl radicals containing from 1 to 10 carbon atoms and more preferably are alkyl hydrocarbon radicals containing from 1 to 5 carbon atoms including methyl, ethyl propyl, isopropyl, n-butyl, sec. butyl, isobutyl, n-amyl, isoamyl, and the like; A is a linear saturated aliphatic radical containing from 14 to 18 carbon atoms in its chain; n is an integer of either 1 or 2; and y is an integer from 0 to 2. The total number of carbon atoms in A and the side chains thereof is 18. R and R may be the same or may be difierent alkyl radicals. Representative dialkyl esters found useful in this invention include dialkyl 1,20-eicosane dioate, dialkyl S-ethyl octadecane-l, l8-dioate, dialkyl dimethyl octadecane-1,18- dioate, dialkyl diethylhexadecane-l,l6-dioate and the like, where the dialkyl groups are methyl, ethyl, propyl, and the like including alkyl hydrocarbon radicals containing from 1 to 5 carbon atoms. Mixtures of any of the materials described above may also be used. For example, mixtures of above 20 to weight percent of dimethyl l, 20-eicosane dioate and about 80 to 20 weight percent of dimethyl 8-ethyl octadecane-1,18-dioate are quite useful. The amounts of necessary reactants employed to make the modified polyesters, on a molar basis, are ordinarily one mole equivalent of a mixture of the two types of dialkyl esters of aromatic and C dicarboxylic acids and a molar excess of the glycol. In the mixture of the dialkyl esters, the dialkyl aromatic dicarboxylic acid esters are present in amounts from about 65 to weight percent and the dialkyl ester of the aliphatic C dicarboxylic acid is present in amounts from about 35 to about 5 weight percent.

Among the modified polyesters and copolyesters which are useful in the practice of the present invention are the polyesters and copolyesters mentioned above modified with chain terminating groups having hydrophilic properties, such as the monofunctional ester-forming polyesters bearing the general formula wherein R is an alkyl group containing 1 to 18 carbon atoms or an aryl group containing 6 to 10 carbon atoms, and m and n are integers from 2 to 22, and x is a whole number indicative of the degree of polymerization, that is, x is an integer from 1 to or greater. Examples of such compounds are methoxypolyethylene glycol, ethoxypolyethylene glycol, n-propoxypolyethylene glycol, isopropoxypolyethylene glycol, butoxypolyethylene glycol, phenoxypolyethylene glycol, methoxypolypropylene glycol, methoxypolybutylene glycol, phenoxypolypropylene glycol, phenoxypolybutylene glycol rnethoxypolymethylene glycol, and the like. Suitable polyalkylvinyl ethers having one terminal hydroxyl group are the addition polymers prepared by the homopolymerization of alkylvinyl ethers wherein the alkyl group contains from 1 to 4 carbon atoms. Examples of such chain-terminating agents are hydroxy polymethylvinyl ether, hydroxy polyethylvinyl ether, hydroxy polyprop-ylvinyl ether, hydroxy polybutylvinyl ether, hydroxy polyisobutylvinyl ether, and the like. The chain-terimnating agents or compounds may be employed in the preparation of the modified polyesters, in amounts ranging from 0.05 mole percent to 4.0 mole percent, based on the amount of dicarboxylic acid or dialkyl ester thereof employed in the reaction mixture. It is to be noted that when chain-terminating agents are employed alone, i.e., Without a chain-branching agent, the maximum amount that can be employed in the reaction mixture is 1.0 mole percent. Thus, unexpectedly, the addition of controlled amounts of chain-branching agents along with the chain-terminating agents allows the introduction of an increased amount of the latter into the polymer chain than is otherwise possible when employing the chain-terminating agents alone.

One will readily appreciate that the Weight percent of chain-terminating agent which may be employed in this invention will vary with the molecular weight of the agent. The range of average molecular weight of the chain-terminating agents suitable for use in this invention is from 500 to 5000, with those agents having a molecular weight in the range of 1000 to 3500 being preferred.

Materials suitable as chain-branching agents or crosslinking agents, which are employed to increase the viscosity or molecular weight of the polyesters, are the polyols which have a functionality greater than two, that is, they contain more than two functional groups, such as hydroxyl. Examples of suitable compounds are pentaerythritol; compounds having the formula wherein R is an alkylene group containing from 3 to 6 carbon atoms and n is an integer from 3 to 6, for example, glycerol, sorbitol hexane triol-l, 2, 6, and the like; compounds having the formula wherein R is an alkyl group containing from 2 to 6 carbon atoms, for example, trimethylol ethane, trimethylol propane, and the like compounds up to trimethylol hexane; and the compounds having the formula F L( 2)u 3 wherein n is an integer from 1 to 6. As examples of compounds having the above formula there may be named trimethylol benzene-1,3,5, triethylol benzene-1,3,5, and the like.

Aromatic polyfunctional acid esters may also be employed in this invention as chain-branching agents and particularly those having the formula and in which, R, R and R" are alkyl groups containing 1 to 3 carbon atoms and R' is hydrogen or alkyl groups having 1 to 2 carbon atoms. As examples of compounds having the above formula there may be named trimethyl trimesate, tetramethyl pyromellitate, tetramethyl mellop-honate, trimethyl hemimellitate, trimethyl trimellitate, tetramethyl prehnitate, and the like. In addition, there may be employed mixtures of the above esters which are obtained in practical synthesis. That is, in most instances when preparing any of the compounds having the above formula, other related compounds having the same formula may be present in small amounts as impurities. This does not affect the compound as a chain-branching agent in the preparation of the modified polyesters and copolyesters described herein.

The chain-branching agents or cross-linking agents may be employed in the preparation of the polyesters and copolyesters in amounts ranging from 0.05 mole percent to 2.4 mole percent, based on the amount of dicarboxylic acid or dialkyl ester thereof employed in the reaction mixture. The preferred range of chain-branching agent for use in the present invention is from 0.1 to 1.0 mole percent. In the practice of the present invention, the calculated amounts of chain-terminating agent or chain-terminating agent and chain-branching agent or cross-linking agent are charged to the reaction vessel at the beginning of the first stage of the esterification reaction and the reaction proceeds as in any well-known esterification polymerization.

The highly polymeric linear condensation polymers selected from the group consisting of polyesters and polyester-amides, which contain in the molecular structure a substantial proportion of recurring groups having the following structural formula CH -CH:

oH-orn-oon,on,

wherein the substituted cyclohexane ring is selected from the group consisting of the cis and trans isomers thereof may be used in the practice of this invention. These polymeric linear polyesters and polyester-amides may be prepared by a process comprising condensing (1) either of cis or the trans isomer or a mixture of these isomers of l,4-cyclohexanedimethanol alone or mixed with another bifunctional reactant with (2) a bifunctional carboxy compound.

The bifunctional reactants which can be employed contain no other reactive substituents which would interfere with the formation of a highly polymeric linear polymer when condensed with 1,4-cyclohexanedimethanol or a mixture thereof with such bifunctional reactants. These 'bifunctional reactants adapted for the preparation of linear condensation polymers are quite well known and have been discussed earlier.

The 1,4-cyclohexanedimethanol employed in any of the processes for making condensation polymers can be used in combination with an additional bifunctional coreactant such as when employing a mixture of glycols (it is advantageous to use amounts of the 1,4-cyclohexanedimethanol equal to at least 50 mole percent of the total of such coreactants employed although smaller proportions can also be used). The various bifunctional core actants which can be employed in admixture with 1,4- cyclohexanedimethanol include other glycols and compounds which do not necessarily react with a glycol e.g. an aminoalcohol. Such coreactants also include diamines, or aminocarboxy compounds.

The bifunctional reactants containing functional groups which can be condensed with 1,4-cyclohexanedimethanol or mixtures thereof are bifunctional compounds capable of condensation so as to form highly polymeric linear condensation polymers Such bifunctional compounds can be solely inter-reactive with a glycol, e.g. a dicanboxylic acid or they can 'be both (a) coreactive in the sense they can be used in lieu of or as a partial replacement of the glycol in a polyester, and (b) inter-reactive in the sense that they condense with a glycol or a bifunctional compound which can be employed in lieu of a glycol. For example, 6-amino-caproic acid is both coreactive in that the amino group is of the type which can be used in lieu of a hydroxy radical of a glycol and also inter-reactive in the sense that the carboxylic group will react with the hydroxy of a glycol or the amine of a bifunctional compound which can be used in lieu of a glycol. The bifunctional compounds which are solely inter-reactive with a glycol include dicarbox'ylic acids, carbonates, and the like. The other bifunctional inter-reactive compounds include aminocarboxy compounds, or hydroxy carboxy compounds.

The modified linear condensation polyesters, used in accordance with the present invention, have specific viscosities in the range of about 0.1 to about 1.0, which repre- )7 sent fiber-and-filament-forming polymers. Specific viscosity, as employed herein, is represented by the formula where sD Rel.

N Time of flow of the polymer solution in seconds Time of fiow of the solvent in seconds Viscosity determination on the polymer solutions and solvent are made by allowing said solutions and solvent to flow by gravity at 25 C. through a capillary tube. In all determinations of polymer solution viscosities, a polymer solution containing 0.5 percent by weight of the polymer dissolved in a solvent mixture containing two parts by weight of phenol and one part by weight, of 2,4,6-trichlorophenol, and 0.5 per-cent by weight of Water based on the total weight of the mixture, was employed.

The aqueous emulsions which are used in the practice of this invention may contain up to 20 percent solids by weight without exceeding the viscosity limits normally used for conditioning agents used in yarn production, with from about 2 to about 15 percent solids being generally preferred. By the term solids as used herein, there is meant the totality of ingredients exclusive of the aqueous vehicle without regard to physical state.

Conventional methods may be employed in formulating the .aqueous emulsion. A simple and convenient method is merely to heat the solid material until it melts, and then add the molten material to the aqueous vehicle with vigorous mechanical agitation. During this addition step, the water should be maintained at an elevated temperature which is at or above the melting point of the material.

Generally, good results are obtained in both cold and hot drawing operations when the conditioning agent is applied in an amount such that the solids deposited on the fiber constitute from about 0.1 to about 1.5 percent based on the weight of the fiber. Although lesser or greater amounts may be used, best results are obtatined when the amount of solids deposited on the fiber is within this range.

As has been emphasized, the above-described treating agent is applied to the filaments or fiber immediately during or after spinning and prior to drawing. A conventional and convenient technique of application is to contact the fiber while moving or advancing in the course of production with a roll which is made to rotate so that its lower portion dips into a pan containing the treating composition. The treating agent is pumped from a reservoir to the pan or other container and a constant level is maintained by an overflow pipe or similar device. Other suitable methods and devices may be employed such as the use of a wick or split roll or the fiber may be passed through a bath containing a treating agent.

The fibers herein described may be modified by incorporation therein of various modifying agents. Illustrative of suitable modifying agents that may be incorporated into the fibers are pigments, plasticizers, resins, diluents, water repellents, waxes, luster modifying agents, flame repellents, antistatic agents, softeners, and the like.

The following examples specifically illustrate the manner in which the process of the present invention is conducted and the advantages obtained there-by. That is, advantages which accrue both with respect to improvement of the drawing operation as well as in the ultimate yarn products. The examples are given by way of illustration only and are not to be construed as limitative.

Example 1 Filaments were formed by the melt extrusion of a polyethylene terephthalate polymer modified with approximately 6 percent, based on the weight of the polyethylene terephthalate, of methoxy polyethylene glycol having a molecular weight of about 2,000, and approximately 0.125

percent, based on the weight of the polyethylene terephthalate, of pentaerythritol. N-o finish was applied to these filaments. The filaments were than lagged or held for 17 hours at room temperature, about 23 C., after which time they could not be uniformly cold or hot drawn. Additional filaments were lagged 8 days at room temperature at which time they could not be cold drawn, and when hot drawn they were so brittle at a draw ratio of 5.2 that a continuous drawing line could not be maintained over a short time period of 5 minutes.

Example 2 Filaments were formed by the melt extrusion of polyethylene terephthalate modified with approximately 6 percent, based on the weight of the polyethylene terephthalate, of methoxy polyethylene glycol having a molecular weight of about 2,000, and approximately 0.125 percent, based on the weight of polyethylene terephthalate, of pentaerythritol. These filaments were then treated with an aqueous emulsion containing 10 percent solids, the solids content of which comprised soya dimethyl ethyl ammonium ethosulfate. The treating agent was applied by means of a rotating roll in an amount such that 0.69 percent solids were deposited on the filaments, based on the weight of the filaments. The filament yarns were then divided into three parts. The first part was immediatelyhot drawn on a conventional draw-twist machine at a draw ratio of 4.41X with excellent results. The second part was lagged for 7 days after which it was hot drawn on a conventional draw-twist machine at a draw ratio of 4.41X with excellent results. The third part was lagged for 31 days after which it was hot drawn on a conventional draw-twist machine at a draw ratio of 4.41X with excellent results.

As various changes in modification of this invention can be made without sacrificing any of its advantages and without departing from the spirit and scope thereof, it is to be understood that all matter herein is to be interpreted strictly as illustrative; as the only limitations of the invention are those which appear in the following appended claims.

What is claimed is:

1. A method of treating polyester filaments which consists essentially of treating said filaments immediately following the extrusion of said filaments with an aqueous consisting essentially of from about 2 to 15 percent by weight of solids, said solids consisting essentially of a cationic surface active quaternary ammonium compound hav ing the formula wherein R represents an alkyl radical having more than 10 carbon atoms and R represents an alkyl radical having less than 5 carbon atoms, lagging said treated filaments for periods of from about 17 hours to about 31 days and thereafter uniformly drawing said treated filaments.

2. A method asdefined in claim 1 wherein the solids content of the aqueous emulsion consists essentially of soya dimethyl ethyl ammonium ethosulfate.

3. A method as defined in claim 1 wherein the polyester is polyethylene terephthalate modified with about 6 percent, based on the weight of the polyethylene tere hthalate, of methoxy polyethylene glycol having a molecular weight of about 2000 and about 0.125 percent, based on the weight of the polyethylene terephthalate, of pentaerythritol.

4. A method of treating polyester filaments which consists essentially of treating said filaments immediately following the extrusion of said filaments with an aqueous emulsion, said solids content of which consists essentially wherein R represents an alkyl radical having more than 10 carbon atoms and R represents an alkyl radical having less than 5 carbon atoms, said solids being deposited on said filaments in an amount of from about 0.1 to 1.5 percent by Weight, based on the weight of said filaments, lagging said treated filaments for periods of from about 17 hours to about 31 days and thereafter uniformly drawing said treated filaments.

1 0 References Cited UNITED STATES PATENTS 2,668,785 2/1954 Jefferson 2528.75 X 3,113,369 1'2/1963 Barrett 2528.8 3,113,956 12/11963 Robinette 2528.75 3,167,531 1/1965 Parker et al. 260-77 ALEXANDER H. BRODMERKEL, Primary Examiner.

10 ROBERT F. WHITE, Examiner.

F. S. WHISENHUNT, A. H. KOECKERT,

Assistant Examiners. 

1. A METHOD OF TREATING POLYESTER FILAMENTS WHICH CONSISTS ESSENTIALLY OF TREATING SAID FILAMENTS IMMEDIATELY FOLLOWING THE EXTRUSION OF SAID FILAMENTS WITH AN AQUEOUS CONSISTING ESSENTIALLY OF FROM ABOUT 2 TO 15 PERCENT BY WEIGHT OF SOLIDS, SAID SOLIDS CONSISTING ESSENTIALLY OF A CATIONIC SURFACE ACTIVE QUATERNARY AMMONIUM COMPOUND HAVING THE FORMULA 